Proceedings of ICIS SGCR-WIRES 2024, held jointly with the 23rd International Cancer Imaging Society Annual Conference, collaborating with the Singapore Radiological Society and College of Radiologists Singapore

and Uncertainty-inspired Open Set (UIOS). Their performance was assessed using the Area Under the Curve (AUC) of the Receiver Operator Characteristic. The DenseNet169 model achieved an AUC of 0.9767, the DenseNet169 + SWAD model had an AUC of 0.9805, and the UIOS model had an AUC of 0.9767. Conclusions: This study demonstrates a promising alternative indicator for diagnostic AI for conditions outside of trained diagnoses, with all three models showing a high classification accuracy. Incorporating uncertain probability increases the transparency and explainability of AI-driven diagnostic tools by identifying instances where predictions are likely to be unreliable and can prompt dedicated review by a radiologist.


Material(s) and Method(s):
This is a multi-institutional and retrospective study conducted from 2009 to 2018.Patients with ovarian cancer who underwent CT at the time of diagnosis were included.Patients were followed for at least 5 years after diagnosis or until death, whichever occurred first.Total measurements of psoas muscle, skeletal muscle, covering cross-sectional area and mean pixel intensity, alongside with the evaluation of fat compositions (including subcutaneous and visceral) at L4 vertebral level were obtained.Survival associations with changes in muscle measurements and fat compositions were evaluated using uni-variate and multivariate stepwise Cox proportional hazard analyses.All p-values were considered significant < 0.05.

Results:
A total of 496 patients were included (mean age ± SD, 49.3 ± 15.3 years; pT1 n = 233, pT2 n = 42, pT3 n = 221).Using the stepwise analysis, the subcutaneous fat mean density, pathological T and M stage, and age, were independently predictive for overall survival (hazard ratios (HR) 1.028, 6.102, 1.776 and 1.026, all p < 0.05), when normalized with pathological stage, histopathological types, age and status of resection margin.In subgroup analysis, the subcutaneous fat mean density remained an independent predictor for overall survival, in both early (pT1 and pT2) and late stage (pT3) ovarian cancers.

Conclusions:
Changes in subcutaneous fat composition upon the diagnosis of ovarian cancer could be an independent prognostic indicator for overall survival.

O6 AI-powered automated tool for delineation of focal bone lesions and measurement of quantitative imaging biomarkers in Multiple Myeloma patients using Whole-Body Diffusion Weighted Imaging (WBMRI)
Antonio Candito 1 , Matthew D. Blackledge 2 , Richard Holbrey 2 , William Weston 3 , Francesca Castagnoli 3 , Alina Dragan 3 , Christina Messiou 3 , Dow-Mu Koh 3 1 MRI Physics, The Institute of Cancer Research, United Kingdom; 2 The Institute of Cancer Research, United Kingdom; 3 The Royal Marsden NHS Foundation Trust, United Kingdom Cancer Imaging (2024),24 (1): O6 Objectives/ Teaching Points: WBMRI is recognised as the most sensitive imaging modality for detection of focal myeloma bone marrow lesions which are an integral part of diagnostic criteria.We have developed an automated tool to localise and delineate focal bone lesions from WBMRI which enables calculation of the Total Diffusion Volume (TDV, in millilitres) and the Apparent Diffusion Coefficient (ADC).

Material(s) and Method(s):
We used two retrospective, anonymised cohorts: a multi-centre cohort with 650 WBMRI scans from patients with multifocal and metastatic diseases, and a single-centre cohort with 66 patients diagnosed with multiple myeloma.Experienced radiologists manually delineated focal bone lesions in all 66 WBMRI scans.The automated tool consists of five stages: (i) pre-processing raw DICOM images to compute b-value images and the ADC map; (ii) generating a signal b900 normalised image and a skeleton probability atlas map using a semi-supervised deep learning model developed from the multi-centre cohort; (iii) generating a mask of restricted diffusion bone lesions (high b900 signal and ADC > 600 mm /s) using a supervised shallow network trained on the single-centre cohort and images from (ii); (iv) excluding treated lesions (ADC > 1300 mm /s) using a post-processing algorithm; (v) generating a structured report with TDV and ADC measurements from the delineated regions.

Results:
The automated tool achieves an average dice score of 0.61 and a precision of 0.73 per scan compared to manual expert delineations on 13 test datasets.The relative differences in median ADC and TDV (log-transformed) are 5% and 15%, respectively.The dice score for detected lesions is 0.68.The computation time for generating delineations and reports from a WBMRI scan is within 80 s.

Conclusions:
Our automated tool can generate fast and accurate delineations of focal bone lesions for measuring WBMRI biomarkers, potentially assisting clinicians in staging patients with multiple myeloma and leading to personalised treatments.

Objectives/ Teaching Points:
To investigate the associations between the hour of the day and Prostate Imaging-Reporting and Data System (PI-RADS) scores assigned by radiologists in prostate MRI reports.

Material(s) and Method(s):
Retrospective single-centre collection of prostate MRI reports over an 8-year period.Mean PI-RADS scores assigned between 0800 and 1800 h were examined with a regression model.

Results:
A total of 35′004 prostate MRI interpretations by 26 radiologists were included.A significant association between the hour of day and mean PI-RADS score was identified (Beta = 0.005, p < 0.001), with malignant scores more frequently assigned later in the day.

Conclusions:
These findings suggest chronobiological factors may contribute to variability in radiological assessments.Though the magnitude of the effect is small, it may potentially add variability and impact diagnostic accuracy.

O8
Using ChatGPT to change free text reports into structured reports for staging CT scans Mina Ibrahim, Mark Bekhit Department of Radiology, Auckland City Hospital, New Zealand  Cancer Imaging (2024),24 (1): O8 Objectives/ Teaching Points: Accurate and consistent radiology reporting is crucial for effective cancer staging and treatment planning.While structured reports are preferred for their clarity, existing software often requires distracting manual input, leading to the continued use of variable free-text reports.Large Language Models like ChatGPT offer a promising solution to automate the conversion of free-text CT scan reports into structured formats, enhancing communication without increasing radiologists' effort.Studies have explored ChatGPT's applications in radiology, such as simplifying reports for patients, extracting data, and generating diagnostic suggestions.Recently, promising results have been seen in converting free-text reports into structured formats for thyroid ultrasounds.However, no research has yet investigated its use in converting free-text reports for oncology staging CT scans.This study aims to assess ChatGPT's potential to standardize oncology reporting, enhance data interoperability, and improve cancer care quality.

Material(s) and Method(s):
We conducted a retrospective study of 101 staging CT Chest/Abdomen/Pelvis scans from our institution.CT studies were excluded if they had been reported using the preferred oncology structured template.Using GPT-4, ChatGPT (Mar 23 Version) converted original free-text reports into structured reports based on our preferred oncology template.The accuracy of these AI-generated reports was evaluated, with errors categorized as major or minor based on whether they pertained to key findings in the report conclusion.

Results:
Of the 101 staging CT scans, 99 (98%) were correctly structured.15 (15%) contained major errors and 54 (53%) contained minor errors.increases were subsequently self-resolved, whereas those with ALP exceeding 1.5 times of reference ranges had occult pathology.A Fisher exact test was conducted for the degree of ALP increase and its correlation with metastasis.There was a significant association between a > 1.5 times increase and metastasis, with a P value of 0.029.

Conclusions:
It is suggested that bone scan referrals should be prioritized if there is an isolated ALP increase over 1.5 times of the reference range.

Objectives/ Teaching Points:
To study the impact of using 'PAUSE' to communicate imaging findings in advanced primary epithelial ovarian cancer (EOC) on MDT decisionmaking and cytoreductive surgery outcomes.

Material(s) and Method(s):
This is a prospective study on stage III and above EOC patients who underwent CECT for disease evaluation and received advice from the Gyne-oncology MDT between July 2022 and May 2024.Two radiologists document imaging findings using PAUSE system, and correlated these with MDT decisions, treatment, and the outcome of cytoreductive surgery.

Conclusions:
Components of "PAUSE" and PAUSE score significantly influenced MDT decision-making and the treatment given to patients with advanced epithelial ovarian cancer.

O13
Choroid Plexus Uptake on Amyloid PET as an Early Predictor of Cortical Amyloid Deposition in Amyloid-negative Individuals across the Alzheimer's Disease Continuum Yoon Seong Choi, Pek-Lan Khong Diagnostic Radiology, National University of Singapore, Singapore Cancer Imaging (2024),24 (1): O13 Objectives/ Teaching Points: Alzheimer's disease (AD) is marked by the progressive accumulation of amyloid plaques, with early detection being crucial for intervention strategies.The aim was to investigate the predictive capacity of choroid plexus (CP) uptake on amyloid PET for cortical amyloid deposition and future amyloid-positive conversion among amyloid-negative individuals, potentially serving as an early biomarker for AD.

Material(s) and Method(s):
We analyzed amyloid-negative participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI, n = 634) and Harvard Aging Brain Study (HABS, n = 205) cohorts.The study analyzed amyloid PET standardized uptake value ratio (SUVR) in CP and cortical regions and cerebrospinal fluid (CSF) amyloid-beta 42 (Aβ42) levels.The prognostic value of baseline CP SUVR was assessed using linear regression for predicting the rate of future increase in cortical SUVR that was extracted by linear mixed model from repeated amyloid PET scans, and using Cox regression for predicting future amyloid-positive conversion.Baseline cortical SUVR, age, sex, education, APOE4 status were used as covariates.Mediation analysis was performed with CP SUVR as a mediator between CSF Aβ42 and cortical SUVR.Results: 88 (18.5%)ADNI and 21 (13.0%)HABS participants progressed to amyloid-positive status over a median follow-up of 4.0 and 2.9 years, respectively.CP SUVR was independently prognostic for predicting the rate of cortical SUVR increase in both ADNI (b = -0.015,SE = 0.015) and HABS (b = -0.016,SE = 0.004, P < 0.001) cohorts.CP SUVR was also independently prognostic for predicting future amyloid-positive conversion in the ADNI (HR 0.06 [0.01-0.25],P < 0.001 in the ADNI) and was borderline significant in the HABS (HR 0.03 [< 0.01-1.61],P = 0.082).In mediation analysis, CP SUVR significantly mediated the association between CSF Aβ42 and cortical SUVR (b = 0.04 [0.01-0.07],P < 0.001 for indirect effect).

Conclusions:
CP SUVR from amyloid PET scans is a useful biomarker for predicting future amyloid deposition.It has the potential to improve the costeffectiveness of amyloid PET scans in monitoring amyloid-negative individuals for early detection of amyloid-positive conversion.Further validation of CP SUVR is needed to evaluate its robustness and generalizability in preclinical Alzheimer's disease diagnosis.

Objectives/ Teaching Points:
To determine the utility of Gallium-68 DOTATATE imaging in clinical management for phaeochromocytomas.

Material(s) and Method(s):
Retrospective review of multidisciplinary meeting (MDM) documentation and clinical records between Jan 2022-March 2024 was conducted to assess the utility of Gallium-68 DOTATATE PET imaging in clinical decision making of adrenal tumours.Qualitative and quantitative analysis Gallium-68 DOTATATE PET and FDG PET findings including SUVmax and contralateral SUVmax, contrast CT findings including size of tumour, stage of tumour, serological markers, histopathology result and management plan was conducted.

Results:
A total of 150 patients were discussed in the multidisciplinary setting for phaeochromocytomas.There were 20 malignant adrenal tumours and 15 phaeochromocytomas on histopathology result.MDM decision making was analysed to determine whether or not the use of DOTATATE imaging affected management options.There was no incomplete excision of tumour and no mortality in this series.

Conclusions:
The use of DOTATATE imaging may confirm diagnosis of phaeochromocytoma, however given clinical suspicion and serological markers provided by the clinician, this information did not appear to alter the course of clinical management.DOTATATE low avidity and FDG PET increased avidity may predict histopathological malignant phaeochromocytoma.

Material(s) and Method(s):
Patients with suspected prostate cancer, PI-RADS 2 or 3 on mpMRI, and who had a pelvic only [68 Ga]Ga-PSMA-11 PET/CT were included.The non-furosemide group (PRIMARY trial) was compared with the furosemide group (PRIMARY2 trial) who received furosemide 20 mg IV at time of radiotracer injection.A pelvic-only PET/CT was acquired between 60 and 70 min, without intravenous contrast.Ordered subset expectation maximisation (OSEM) algorithm was used for tomographic reconstruction.Quantitative parameters of the bladder (SUVmax and volume) were measured by two experienced nuclear medicine physicians using an edge-detection tool.95% confidence intervals were calculated using t-distributions.

Objectives/ Teaching Points:
This study aims to evaluate the incidence, follow-up outcomes, and risk factors associated with intravenous contrast media extravasation during CT scans utilizing a power injector in a large cohort.This research seeks to enhance our understanding of this complication and inform strategies for its prevention and management in clinical practice.

Material(s) and Method(s):
This retrospective study encompassed patients who received intravenous (IV) contrast-enhanced CT scans from January 2015 to December 2023.Each incidence of extravasation was digitally documented in Radiology Information System (RIS).Institutional Review Board exemption was obtained.Data on the frequency of extravasation were collected, along with patient demographics, injection parameters, and follow-up outcomes.Potential risk factors such as age, patient setting, type of examination, venous access site, injection rate, and contrast extravasated volume were analyzed using logistic regression models to identify significant predictors of extravasation.

Results:
577 patients encountered contrast extravasation, resulting in a rate of 0.3%.The predominant trend in follow-up outcomes was an improvement, a favourable outcome.Notable risk factors, including age > 70 years old, female, inpatient setting, and higher injection rate demonstrated significant associations with extravasation.

Conclusions:
Contrast extravasation during CT scans with power injectors records higher frequency though the majority outcome is improved over the next few days.Identifying high-risk patients through predictive factors can aid in implementing preventive strategies to minimize the incidence and improve patient safety.

Poster presentations P1 Navigating T Staging of Nasopharyngeal Cancer (American Joint Committee on Cancer (AJCC) 8th edition) with Case Illustrations
Josefina Marie Medina Radiology, St. Luke's Medical Center, Philippines Cancer Imaging (2024),24 (1): P1 Objectives/ Teaching Points: Nasopharyngeal carcinoma (NPC) staging is crucial for determining prognosis and treatment.The American Joint Committee on Cancer (AJCC) 8th edition T staging provides a detailed framework for understanding the local spread of NPC.This exhibit reviews T1 to T4 stages, emphasizing key anatomic landmarks and common patterns of tumour spread that radiologists should know, illustrated with clinical cases.

T1 Stage:
• • Tumour confined to the nasopharynx or extends to the oropharynx and/or nasal cavity without parapharyngeal extension.• • Rosenmuller fossa is the most common site for NPC to arise.• • Spread to the nasal cavity often limited to the posterior aspect.
• • Inferior extension to the oropharynx is uncommon.

T2 Stage:
• • Tumour spread to the parapharynx, involving the levator palatini muscle, pharyngobasilar fascia, and parapharyngeal fat space.• • Tumour spread can compress the eustachian tube, leading to middle ear and mastoid effusion.• • Involvement of adjacent soft tissues, including medial and lateral pterygoid muscles, and prevertebral muscles.• • Further spread may involve the carotid space, encasing the carotid artery.

T4 Stage:
• • Intracranial invasion commonly involves the cavernous sinus and dura of the cranial fossae, leading to multiple cranial nerve palsies.• • Tumour may spread from the orbital fissures or skull base foramina.• • Extensive soft tissue involvement beyond the lateral pterygoid muscle, including the infratemporal fossa.Objectives/ Teaching Points: Background The International Federation of Gynaecology and Obstetrics (FIGO) staging system for endometrial cancer was updated in 2023.The update incorporates pathology and molecular classifications into the staging system and appears complex.Staging would now require a multi-disciplinary approach.There is likely to be a change in the role of imaging in the management of endometrial cancer and a shift in the referral pattern to imaging services.Teaching points 1.In this educational exhibit we list the differences between the updated FIGO (2023) staging system and the previous 2007 staging system for Carcinoma Endometrium.
2. We display the various clinical scenarios with which patients may be referred to Radiology services and how to choose appropriate imaging modalities.3. We display specific changes we need to make to the Endometrial Cancer reporting template to incorporate the recommendations of updated FIGO staging system.4. We display imaging examples to demonstrate these specific points.

P4
Adrenal Lesions-Not always an adrenal adenoma James Fish, Katherine Ordidge, Anju Sahdev Radiology, Barts Health NHS Trust, United Kingdom Cancer Imaging (2024),24 (1): P4 Objectives/ Teaching Points: • • Adrenal incidentalomas are commonly found in routine practice on up to 5% of all abdominal CT imaging.• • Clear guidelines exist as to the management of adrenal incidentalomas; including their initial characterisation on imaging (CT, MRI and PET-CT).• • Whilst the majority (> 90%) of incidentally detected, asymptomatic adrenal lesions are benign adrenocortical adenomas, there are important differentials of which the radiologist must be aware.• • Confident imaging characterisation of adrenal lesions helps ensure that patients follow the correct clinical management pathways and avoid expensive and unnecessary follow-up, including adrenal biopsy.

Table of Contents/Outline:
Case based educational exhibit with multiple examples of both benign and malignant adrenal conditions and their associations with referenced teaching points to include: Benign Adrenal lesions: --Evaluation of classical imaging characteristics of adrenal adenomas on CT and MRI imaging including lipid-rich and lipidpoor subtypes with cross-correlation to functional status.

Malignant Adrenal lesions:
--Delineate imaging characteristics which should raise the suspicion of adrenal malignancy; both primary and secondary malignancy and in turn avoid unnecessary investigations or upstaging of patients.
--Array of malignant adrenal pathology including phaeochromocytomas, adrenocortical carcinomas, metastases to the adrenal gland, malignant neuroendocrine tumours and composite tumours.

Indeterminate Adrenal lesions:
--Lesions that are not clearly benign or malignant on initial imaging remain a challenge to radiologists.

Objectives/ Teaching Points:
There have been significant advancements in the understanding of the pathology, molecular characteristics, treatment options and clinical outcomes of endometrial carcinoma.This has necessitated FIGO to revise its staging classification to incorporate and reflect these new knowledge and data.The key changes in the current staging system will be highlighted along with comparison to the previous FIGO 2009 system.Each stage of endometrial carcinoma will be described in detail and illustrated by MRI examples.The impact it has upon the MRI interpretation, radiological staging and subsequent management of patients will be discussed.Therefore, it is essential for radiologists to acquaint themselves with the updated staging classifications and comprehend its influence on the management of endometrial carcinoma.The goals of this poster are to review response assessment criteria for prostate cancer lesions using PCWG3 and RECIST 1.1.The reader will review the evolution of criteria, learn how to select and document visceral and osseous disease assessment at baseline, calculate tumour burden, review methodology for tracking lesions on follow up, assigned timepoint specific response assessments, and formulate an integrated over response assessment.This educational exhibit will use illustrative figures and example bone scan/CT to demonstrate examples of baseline and various response scenarios in prostate cancer patients undergoing treatment and instruct the reader how to formulate an accurate assessment.Specific teaching points include baseline lesion selection, treatment flare progression at first follow up (2 + 2 rule), and progression after first follow up.Concluding, in the era of precision prostate cancer treatment, radiologists are required to have increased awareness and familiarity with novel response assessment criteria.As important members on the cancer care team, radiologists must be aware and familiar with PCWG3 modified RECIST 1.1 response assessment criteria, both in the setting of clinical trial reading and routinely at the workstation.

P7
Every aortic valve tells a story -a pictorial essay of CT cardiac gated imaging of the aortic valve Wai Keat Lau 1 , Ching Ching Ong 2 , Yun Song Choo 2 , Yinghao Lim 3 , Ivandito Kuntjoro 3 , Lynette Li San Teo 2 1 NUHS, Singapore; 2 Department of Diagnostic Imaging, National University Hospital, Singapore; 3 Department of Cardiology, National University Hospital, Singapore Cancer Imaging (2024),24 (1): P7 Objectives/ Teaching Points: Aortic stenosis is the most common valvular heart disease in developed countries.Transcatheter Aortic Valve Implantation (TAVI) is now an established treatment option in patients who are ineligible for surgery or high risk surgical candidates.Over the years, TAVI is also increasingly being used in patients at intermediate risk for conventional surgical valve replacement.With advances in computed tomography (CT) imaging, CT is now the gold standard for preprocedural evaluation of potential TAVI patients.Most patients with severe aortic stenosis have degenerate valves and these are usually seen as trileaflet calcified aortic valves.There are also less common causes of aortic valve dysfunction that undergo TAVI procedures and these include bicuspid aortic valve morphology, rheumatic heart disease and previous radiation to the chest with involvement of the aortic valve leaflets.Of note, the bicuspid aortic valve annulus has a more elliptical shape with asymmetric annular calcification; this can affect transcatheter valve frame expansion resulting in increased procedural complications such as paravalvular leak and aortic root injury.This pictorial essay demonstrates the typical degenerate trileaflet aortic valve with a high Agatston score and also aims to highlight the other less common causes of aortic valve dysfunction on cardiac gated CT heart scans.These include bicuspid aortic valves, as well as valves affected by rheumatic heart disease or prior radiation.The distinctive features of each will be discussed.

P8 Tuberculous Arthropathy: What the Radiologist Should Know-A Review of Imaging, Microbiological and Treatment Considerations
Aric Lee 1 , Amanda Koh 2 1 Department of Diagnostic Imaging, National University Hospital, Singapore; 2 Tuberculosis Control Unit, Tan Tock Seng Hospital, Singapore Cancer Imaging (2024),24 (1): P8 Objectives/ Teaching Points: Tuberculous (TB) arthropathy remains a concern in endemic countries and among migrant populations.Early diagnosis and anti-TB therapy are crucial for functional recovery, yet clinical features can be nonspecific, and concomitant pulmonary TB is sometimes absent.Radiologists should maintain a sufficient degree of suspicion in high-risk patients presenting with progressive joint symptoms.Patients typically present with subacute-chronic monoarthritis characterised by pain, swelling and functional impairment, predominantly affecting medium to large joints.Two distinct pathologic variants exist: an indolent granular variant seen in adults, and a juvenile caseous exudative variant associated with bone erosion, abscesses and sinuses.
We present a case series demonstrating radiological findings important for diagnosis and management.Initial radiographs often reveal joint effusions and peri-articular osteopaenia, followed by cortical and joint destruction.CT is useful in complex anatomical regions and to guide biopsy.MRI allows identification of marrow oedema, necrosis, abscesses, and synovial changes (including 'rice' bodies), as well as sinus tracts and extra-articular features including tenosynovitis, bursitis and myositis.Microbiological confirmation through joint aspiration or biopsy is essential, with samples undergoing acid-fast bacilli smears, culture, and nucleic acid amplification tests (NAATs).Advanced NAATrifampicin resistance assays like BDMax and Xpert MTB/RIF enhance sensitivity and complement traditional diagnostics by rapidly differentiating TB from nontuberculous mycobacteria and providing crucial drug susceptibility information.Nonetheless, culture remains necessary for final diagnosis.Synovial fluid analysis, while commonly performed, often yields non-specific results.Prompt initiation of anti-TB therapy often obviates surgery and results in favourable functional outcomes.In Singapore, drug-sensitive TB arthropathy is treated with a rifampicin-containing regimen for nine months, though the optimal treatment duration remains uncertain.Surgical interventions like debridement, arthroplasty or arthrodesis may be required for large abscesses, non-viable tissue, or failed medical management.Follow-up relies on clinical assessment due to potential discordance with inflammatory markers and radiographic indicators.

Objectives/ Teaching Points:
Peer learning is a system of peer review in which colleagues provide non-judgemental feedback to each other in an effort to elevate performance across the group.Ongoing feedback about both discrepancies and great calls is given to individuals, high-yield teaching points are shared in routine conferences, and systems improvements enacted where feasible.In the modern oncology era, with a new arena of precision anticancer treatments, Cancer Imaging Peer Learning (CIPL) ensures general radiology practice meets standards of oncology care.Application of CIPL in our department: CIPL assists in the choice of the optimal imaging modality: E.g. including appropriate tracer specific PET/CT and MRI vs CT for assessing response to cytostatic agents.CIPL elevates practice by reducing knowledge gaps about specific therapies: E.g., reviewing the atypical patterns of response to treatment and the side effects of the newest therapies.CIPL elevates practice by sharing diagnostic successes: E.g., detection of grade I toxicity.CIPL identifies systems issues to improve interpretation: E.g., comparison with baseline and nadir scans is needed for correct response assessment.
CIPL identifies patterns of diagnostic discrepancies across radiologists: E.g., perirenal involvement from HemOnc malignancies, sarcoid like reaction versus nodal progression on immunotherapy.CIPL generates improvements by incorporating feedback from oncologists: E.g., a succinct impression providing an overall assessment of tumour burden in the impression instead of listing changes at individual sites of metastases.CIPL facilitates learning between subspeciality sections: E.g., a hip synovial sarcoma and pelvic adenopathy in the same pelvic MRI suggests secondary lymphoma.
In conclusion, CIPL ensures that the general radiologist, in an environment free of judgment, keeps abreast with the continuously evolving precision cancer treatments, to provide better care to patients with cancer.

P10 Metabolic imaging can distinguish ovarian cancer subtypes and detects their early and variable responses to treatment
Ming Li Chia 1 , Kevin Brindle 2 1 Radiology, National University Health System (NUHS), University of Cambridge, Singapore; 2 Cancer Research UK Cambridge Institute, Department of Biochemistry, University of Cambridge, United Kingdom Cancer Imaging (2024),24 (1): P10 Objectives/ Teaching Points: High grade serous ovarian cancer(HGSOC) displays two metabolic subtypes; a high OXPHOS subtype with elevated expression of genes encoding electron transport chain components, increased oxygen consumption and increased chemosensitivity due to oxidative stress and a low OXPHOS subtype that exhibits glycolytic metabolism and higher drug resistance.This project investigated the potential of magnetic resonance spectroscopy (MRS) of hyperpolarized [1-13C]pyruvate metabolism to be used clinically to distinguish low OXPHOS and high OXPHOS tumour deposits in HGSOC patients and to detect their differential responses to treatment.Material(s) and Method(s): HGSOC cells, derived from the ascites of stage 3-4 HGSOC patients, were maintained as patient derived organoids (PDO) and implanted into mice subcutaneously.The resulting tumours were imaged with MRS (hyperpolarized [1-13C]pyruvate metabolism), MRI (Dynamic Contrast Enhanced (DCE)) and with PET (measurements o2fdeoxy-2-[fluorine-18]fluoro-D-glucose uptake).PDO 2(carboplatin sensitive) and PDO 5(Carboplatin resistant) tumour models were treated with i.v.Carboplatin (50 mg/kg) or drug vehicle weekly, with imaging at baseline and weekly thereafter.

Conclusions:
Patient-derived xenografts representative of the different HGSOC metabolic subtypes showed differences in glycolytic metabolism that could be detected with hyperpolarized [1-13C]pyruvate.Myc and EGFR amplification are likely to be responsible for driving increased lactate labelling in the low OXPHOS metabolic subtypes.13C MRS imaging of hyperpolarized [1-13C]pyruvate metabolism has the potential to be used clinically to distinguish low OXPHOS and high OXPHOS tumour deposits in HGSOC patients and to detect their differential responses to treatment.

Objectives/ Teaching Points:
We aim to evaluate the accuracy of radiologists and radiology residents in detection of paediatric appendicular fractures with and without the help of a commercially available fracture detection Artificial Intelligence (AI) solution in the hopes of showing potential clinical benefits in a general hospital setting.

Material(s) and Method(s):
This was a retrospective study.3 Associate/Junior Consultant (AC) radiologists and 3 Senior Residents/Senior Registrars (SR) in Radiology acted as readers in this study.1 reader from each human group interpreted the radiographs with the aid of AI.Cases were categorized into concordant and discordant cases between each interpreting group.Discordant cases were then further evaluated by 3 independent subspecialty radiology consultants to determine the final diagnosis.A total of 250 anonymised paediatric patient cases (aged 2 to 15 years) who presented to a tertiary general hospital which has a Children's emergency were retrospectively collected.Main outcome measures include: presence of fracture, accuracy of readers with and without the help of AI, total time taken to interpret the radiographs.

Results:
The AI solution showed the highest accuracy (Area Under the Curve, AUC 0.97).The two readers aided with AI had higher AUCs compared to readers without AI support.The average accuracy of AC subcategory (AUC 0.84) and SR (AUC 0.88) subcategory were lower compared to the AI algorithm alone.

Conclusions:
To our knowledge, this is the first local study looking at performance of AI against human readers when reading paediatric appendicular fractures.Current commercially available fracture detection AI solutions show potential to improve fracture detection in paediatric limbs and pelvises.This in turn could reduce recall rates and misdiagnoses.Such a solution should be implemented in emergency centres to allow for better quality of care.Background / Outline: Tumours located within the cardiovascular system are rare, regardless if they originated there or from elsewhere.Histologically, some of these are comprised of vascular channels or blood-filled cavities while others are more solid soft tissue masses, and this influences their imaging characteristics.Vascular tumours tend to mimic the blood pool on multiphasic imaging, a feature capitalised on to detect and characterise them in solid organs.Solid tumours, while not enhancing as much as the blood pool, can be discerned by their enhancement relative to surrounding tissues especially if they are more aggressive or hypervascular.When these tumours are located within the blood pool itself, these characteristics may instead aid them in evading detection by blending in with the blood or by masquerading as the much more common hypoattenuating intravascular entity -a clot.

P12 Hiding in Plain
In --Limitations of trans-oral robotic surgery (TORS) include the surgeon's restricted ability to palpate and assess the pharynx, combined with alterations in intra-operative patient positioning due to neck extension, mouth retraction and tongue manipulation.
--Intra-oral ultrasound-guided TORS is a real-time, collaborative approach carried out in theatre.Under general anaesthesia tumour boundaries and depth can be cognitively mapped providing real-time feedback on tumour location and local anatomy.
--Ex-vivo ultrasound assessment can also be performed to assess for macroscopic margins before the end of surgery.

Saline aided intra-oral ultrasound guided biopsy:
--Tissue sampling of retropharyngeal lesions is a technical challenge.Most are not visible (and hence not targetable) with standard percutaneous ultrasound.Biopsy with CT guidance often requires a trans-facial approach and risk injury to local structures including the carotid artery.
--Under general anaesthesia intracavitary flooding with saline acts as a coupling agent to facilitate fine needle aspiration, core biopsy, TORS excision or a combination of techniques.

Ultrasound-guided directly injected therapies (DIT):
--DIT is a developing research field comprised of a range of therapies including immunotherapy, modified oncolytic viruses and peptides, bacteria and chemotherapy. -- The majority of DIT will be performed by oncologists, but a select number of cases will be referred to radiology for imageguided injection. -- The goal of DIT is the higher concentration of drug within the target tumour, and the attenuated systemic adverse event profile.

Objectives/ Teaching Points:
Resistance to platinum-based chemotherapy remains a challenge faced by epithelial ovarian cancer (EOC) patients.Currently, there are no biomarkers to predict chemoresistance.Circulating plasma gelsolin (pGSN) was previously shown to predict chemoresistance in treatment-naïve EOC.Here, we aimed to expand upon pGSN as biomarker by incorporating MRI-based radiomics to improve prediction of chemoresistance in EOC patients.

Material(s) and Method(s):
In this retrospective study, we used the serum collected from 40 EOC patients with paired baseline MRI from the University of Hong Kong between 2016 and 2020.Circulating pGSN was measured from the serum using sandwich ELISA.Radiomic features were extracted from the primary tumour on the apparent diffusion coefficient (ADC) map (b = 0,400,800 s/mm2) using PyRadiomics (version 3.1).Highly correlated features (Spearman correlation coefficient of > 0.9) were removed.Highly repeatable features were selected using elasticnet regression iterated over 100 times for fivefold stratified cross-validations (SCVs) and only those selected > 300 times were considered for further analysis.Mann-Whitney U-test and f-test were conducted to consider statistically significant and repeatable features (p < 0.05) for model building.Grid-search tenfold SCVs was utilized to optimize the hyper-parameters of Gaussian Naïve Bayes classifier to build the prediction model using 6 highly significant features including pGSN.Results: Among the 40 EOC patients (56 ± 11 years old), the majority presented at advanced stage (FIGO III-IV, n = 26).Thirty-three patients were chemosensitive and seven were chemoresistant (progression free interval < 12 months).The proposed framework achieved the following mean performance metrics: area under the curve (0.929), sensitivity (0.900), specificity (0.908) and accuracy (0.920) in predicting chemoresistance.Both pGSN and flatness from the original shape feature contributed more "weight" in the prediction.

Conclusions:
The combined model demonstrated excellent diagnostic ability in predicting chemoresistance in EOC patients, which could promote tailored therapeutics.

Objectives/ Teaching Points:
Cervical spine MRI is crucial in the evaluation of degenerative cervical spondylosis but time-consuming to report.We sought to assess whether a deep learning (DL) model would enhance the speed and accuracy of radiologists with varying experience in reporting such MRIs.

Material(s) and Method(s):
We utilized a previously developed transformer-based DL model to classify spinal canal (grades 0/1/2/3) and neural foraminal (grades 0/1/2) stenoses at each disc level using published scales.The test set included random MRIs (axial T2-weighted gradient-echo, sagittal T2-weighted images) from December 2015 to August 2018 from an external hospital, excluding cases with instrumentation.Two experienced musculoskeletal (MSK) radiologists (12-years' experience each) labelled the test set in consensus (reference standard).Ten radiologists (1-7 years' experience) performed stenosis gradings with and without DL model use, with a 1-month washout period between sessions.Interpretation time (seconds) and interobserver agreement (Gwet's kappa) were assessed.

P19 Change in diffusion-weighted imaging after induction therapy for the prediction of outcomes in advanced nasopharyngeal carcinoma
Qiyong Hemis Ai 1 , Ho-sang Leung 2 , Tsz Shing A. Kwong 2 , Yannis Yan Liang 1 , Linfang Lan 1 , Lun M. Wong 2 , Ann D. King 2 1 Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong; 2 Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Hong Kong Cancer Imaging (2024),24 (1): P19

Objectives/ Teaching Points:
To investigate the predictive value of diffusion weighted imaging (DWI) performed before and after induction chemotherapy (post-IC) for long-term outcome in patients with locoregionally advanced nasopharyngeal carcinoma (adNPC).

Material(s) and Method(s):
This study retrospectively reviewed pre-and post-IC DWIs of 63 eligible patients with adNPC who were treated with IC followed by concurrent chemoradiotherapy (CCRT).DW images with two b-values (0 and 1000 s/mm2) were used to fit a mono-exponential diffusion model to generate the conventional apparent diffusion coefficient (ADC) map.The primary tumour on the pre-and post-IC ADC maps was manually contoured.The mean values of pre-and post-IC ADC (ADCpre and ADCpost-IC), and changes in ADC between pre-and post-IC scans, which were defined as ΔADC% = [(ADCpost-IC-ADCpre)/ ADCpre *100%] were calculated and correlated with disease free survival (DFS) using Cox regression analysis.Significant parameters, together with age, sex, and T-staging, Nstaging, and overall stage were then added into multivariate Cox regression to identify the independent parameters for the prediction of outcomes.

Results:
The 3-year DFS was 86.3%.Univariate analysis showed that high ΔADC% (greater rise in The 3-year DFS was 86.3%.Univariate analysis showed that high ΔADC% (greater rise in ADC on post-IC scan compared with that on pre-treatment scan) correlated with good DFS (HR = 0.959, p = 0.02); but not ADCpre and ADCpost-IC (p = 0.30 and 0.10, respectively).After adjusting the confounding factors, ΔADC% remained independent of being the predictor for DFS (HR = 0.946, p < 0.01).

Conclusions:
Percentage change in ADC value between pre-and post-IC scans, but not absolute ADC values on the pre-and post-IC scans had the potential to be the predictor of long-term treatment response in patients with locoregionally adNPC.

Objectives/ Teaching Points:
As the global population ages, the prevalence of neurodegenerative diseases is expected to rise significantly.Developing accurate and accessible neuroimaging biomarkers for brain age estimation and understanding brain aging gives a deeper insight to the complex processes underlying brain aging and neurodegeneration.This know-how is crucial for developing new therapies and preventive strategies to alleviate the burden of these diseases on individuals, families, and healthcare systems.

Material(s) and Method(s):
Study Population: A balanced dataset of 2000 T1W-MPRAGE brain scans from ethnic Chinese individuals, stratified into 10-year age cohorts, was obtained at Sengkang General Hospital with informed consent and ethical approval.Scans were rigorously reviewed by three board-certified radiologists, and subjects with neurological conditions were excluded.End-to-End Tool: The developed tool automates the analysis pipeline: 1

Objectives/ Teaching Points:
To assess the impact of dilution on multiarterial-phase image quality in liver magnetic resonance imaging (MRI) enhanced with gadoxetic acid (Gd-EOB-DTPA).

Material(s) and Method(s):
This retrospective study included a cohort of 81 patients who had serial gadoxetic acid-enhanced MRI of the liver, first with undiluted, then with 1:1 diluted contrast.The serial MRI examinations were done less than a year apart.Two expert readers independently rated the randomized multi-arterial phase images for anatomic conspicuity, respiratory motion artifacts and overall image quality using a five-point Likert scale.Statistical significance was tested with the Wilcoxon rank test at a significance level of P = 0.05.

Results:
The dilution of gadoxetic acid resulted in significantly better overall image quality (P = 0.04) although neither anatomic conspicuity nor respiratory artifacts showed significant improvement.The mean scores for anatomic conspicuity, respiratory artifacts and overall image quality were 3.72, 3.54 and 3.67 in the diluted group vs 3.59, 3.41 and 3.51 in the undiluted group respectively.

Conclusions:
An imaging protocol involving diluted gadoxetic acid improved overall image quality but do not seem to significantly reduce respiratory artifacts.

Material(s) and Method(s):
Adult patients undergoing upfront colectomy for biopsy-proven colon adenocarcinoma between Jan-July 2022 with adequate preoperative CT abdomen, were selected.Patients with metastases, colon perforation and intussusception, were excluded.T and N staging was done by an experienced radiologist on preoperative CT, and correlation was done with post-operative histopathology using appropriate statistical methods.

Conclusions:
CT showed high PPV for detecting colon wall invasion in locally advanced colon cancers, but the sensitivity and specificity of T and N-staging were modest.Our findings highlight the value of CT for preoperative cancer staging, which can potentially guide the selection of candidates for neoadjuvant therapy in colon cancer.

Objectives/ Teaching Points:
This study aims to reveal imaging features of advanced ovarian carcinoma with special focus on Peritoneal Carcinomatosis Index (PCI) with its prognostic significance.

Material(s) and Method(s):
We conducted a retrospective analysis of patients diagnosed with advanced ovarian carcinoma who underwent imaging assessments (CT and PET-CT) and treatment (upfront debulking surgery / interval standard/advanced debulking surgery/HIPEC) at our institute from October 2011 to March 2024.Detailed analysis of varied appearance of imaging findings of advanced ovarian carcinoma was done.Clinicoradiological correlation was established by comparing preoperative computed tomography (CT) and CT-PCI findings with intraoperative PCI scores.The prognostic value of PCI was determined by analysing its association with disease progression and patient outcomes.

Results:
The study cohort comprised 220 patients exhibiting diverse presentations of advanced ovarian carcinoma on CT scans, demonstrating involvement of the peritoneum, omentum, and mesentery, with lesion sizes spanning 1 to 3. A robust correlation (Pearson correlation coefficient -0.9, p < 0.001) was observed between preoperative CT PCI scores and operative PCI scores.Elevated PCI scores significantly correlated with increased disease progression on follow-up scans in form of omental, peritoneal, organ and bony metastatic lesions.Lower PCI scores correlates with better prognosis and disease free interval/survival.Furthermore, the analysis revealed high specificity and sensitivity of the CT-PCI scoring system in predicting intra-abdominal disease burden, with specificity of 90% and sensitivity of 85% in detecting advanced disease stages.

Conclusions:
Clinicoradiological correlation is vital in determining disease extent and guiding treatment strategies for advanced ovarian carcinoma.The strong relationship between preoperative CT PCI and intraoperative PCI underscores imaging techniques' dependability in predicting intra-abdominal disease involvement.PCI serves as a valuable prognostic indicator, aiding in risk stratification and disease monitoring.
manifestations, imaging features, radiopathological correlation and complications of cardiac angiosarcomas.2. Other rare intravascular tumours and their imaging features, including pulmonary artery sarcomas, intravascular leiomyomatosis, and vascular leiomyosarcomas.

P3 Role of imaging in the staging and management of Carcinoma Endometrium following the 2023 update of the FIGO staging system
• • Invasion of hypopharynx, parotid gland, and orbit indicates advanced local disease.
Objectives/ Teaching Points: Desmoid-type Fibromatosis (DF) is a mesenchymal neoplasm which can involve any body part.It shows unpredictable behaviour ranging from spontaneous regression to locally aggressive disease with high morbidity and mortality.It has significant potential for recurrence.In view of its variable biological and clinical course, the management of DF is challenging and continuously evolving.Watching and waiting is even considered a possible option in a subset of patients.In this poster, we will illustrate DF of different body parts with emphasis on their characteristics and treatment options, including the following: Pregnancy associated abdominal wall DF responding to hormonal agents, FAP associated intrabdominal DF, Sporadic multifocal extremity DF resistant to treatment, Neck DF with local bony invasion, Response of DF to radiation therapy, Response of DF to local IR therapy, Complications of intrabdominal DF from locally aggressive behaviour (small bowel obstruction, hydrosalpinx).In conclusion, DF is a locally aggressive neoplasm of mesenchymal origin, with variable behaviour and a wide range of treatment options, including observation, cytotoxic and cytostatic therapies, surgery, radiation therapy and interventional radiology procedures.Anuradha Chandramohan, Sibangi Pramanik, Sonia Thanikaivelu, Betty Simon, Anu Eapen Department of Radiology, Christian Medical College Vellore, India Cancer Imaging (2024),24 (1): P3

1): P6 Objectives/ Teaching Points:
Recent advancements in PSMA-directed diagnosis and treatment of prostate cancer have led to an explosion in research and new treatment regimens.As with other novel therapies, these new treatments may demonstrate atypical imaging findings, especially early in treatment, which require specific and modified response assessment criteria.At present, many clinical trials for patients undergoing novel prostate cancer treatment utilize an integrated Prostate Cancer Working Group 3 (PCWG3)-modified Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria.
this primary case of an elusive metastatic cardiac angiosarcoma, its appearances on multiple imaging modalities are demonstratedincluding US, CT in the pre-contrast, early and late arterial, portal venous and delayed phases, PET CT and MRI.Its clinical manifestations and associated complications such as haemorrhage and Kasabach-Merritt syndrome are further discussed.A series of secondary cases brings awareness to other rare intravascular tumours that can similarly hide in plain sight.Local paediatric WB-MRI protocols should be further tailored towards specific conditions, optimised towards shorter scan times and complementing functional imaging studies to improve diagnostic yield.
Conclusions:WB-MRI is useful for cancer screening in at-risk patients, especially in older children, as well as in detecting lesions across multiple body sites in paediatric oncology, particularly nodal and osseous/marrow disease.Lung lesions > 9 mm in size are also detectable on WBMRI and may be a useful adjunct to CT thorax for follow up for dominant lung nodules.

Based Morphometric Analysis and Machine Learning Classification of Healthy Controls and Vascular Dementia Using MRI
Bhanu Prakash KN 1 , Kah Meng Ang 2 , Arvind CS 1 , Pulickal Geoiphy George 3 , Philip Yap Lin Kiat 4 , Cheong Chin Yee 4 , Julian Chieng Sau Lian 5 , Cardiovascular diseases are the leading cause of death worldwide.CT imaging is a vital tool that provides crucial information for managing these conditions.The latest advancement in this technology is Photon-Counting Detector (PCD) CT.It offers significant improvements over the traditional Energy Integrating Detector (EID) CT.This poster will highlight the differences between PCD CT and EID CT, look into the technical details and terminology for PCD CT, offer protocol guidance, and showcase clinical applications through case examples.Gallbladder carcinoma is the most common cancer of the biliary system.Unfortunately, the gallbladder cancer is an aggressive tumour and typically presents late, resulting in poor prognosis.It can be challenging to diagnose gallbladder cancer because patients are often asymptomatic or present with non-specific signs and symptoms that may mimic other benign conditions such as chronic cholecystitis (including xanthogranulomatosis cholecystitis), cholesterol polyps, adenomyomatosis as well as other malignancy such as lymphoma, metastasis, or direct invasion of primary liver cancer.Furthermore, the risk factors for gallbladder cancer such as cholelithiasis also overlap with the other benign gallbladder conditions.Early-stage tumours are often incidentally detected at imaging or during cholecystectomy performed for another indication.Typical imaging features of localized disease include asymmetric focal or diffuse thickening of the gallbladder wall, polyps larger than 1.0 cm or a solid mass replacing the gallbladder lumen.Advanced tumours are often infiltrative with adjacent organs invasion and nodal metastasis, and may even present with peritoneal disease.We aim to demonstrate cases of gallbladder carcinoma at different stages of disease as well as their mimics on cross-sectional imaging, providing imaging pearls that may help to suggest the diagnosis of gallbladder cancer.

Investigation of Age-Related Hippocampal Changes in a Large Singaporean Cohort with Gender-Specific Effects
250 T1-weighted MPRAGE scans from ethnic Chinese individuals (50% male, 50% female) were obtained at Sengkang General Hospital, with ethical approval.Participants were stratified into age cohorts, excluding those with neurological conditions.Scans were reviewed by radiologists for quality assurance.The BIDS-formatted data was analysed using Hippunfold, a state-ofthe-art U-Net based automated hippocampal unfolding tool which facilitated precise morphometry and subfield segmentation, yielding volumetric measurements of both left and right CA1, CA2, CA3, CA4, Dentate gyrus (DG), subiculum (Sub), and a combined region encompassing Stratum, Radiatum, Lacunosum, and Moleculare (SRLM).To discern the significance of age-related changes in hippocampal structure, comprehensive statistical analyses Student's t-tests for parametric comparisons, and non-parametric Wilcoxon and Kruskal-Wallis tests to account for potential deviations from normality was conducted.Results:Hippocampal subfield volumes (CA1, CA2, CA3, CA4, Sub, and SRLM) followed similar trends in both hemispheres, with no gender differences in these patterns.Subfield volumes increased until age 30, then decreased for all subfields.Significant differences between genders were found for all subfields except DG in the 21-30 age group.Left and right subiculum volumes showed significant differences up to age 50.Conclusions:This study establishes a normative reference age-related hippocampal subfield volume changes in Singapore's ethnic Chinese population.Consistent trajectories were observed, with volumes increasing until age 30, then declining.While generally no gender differences were found, subtle variations existed in specific subfields.These findings provide a crucial baseline for identifying deviations potentially indicating neurodegeneration, facilitating timely interventions, and improving the quality of life for Singapore's aging population.CT is the modality of choice for staging colon cancers.Neoadjuvant therapies are established in rectal cancer management, but the standard treatment for colon cancer has been upfront surgery.Trials such as FOxTROT are establishing the role of neoadjuvant therapies in downstaging locally advanced colon cancers (T3-T4 stage), thus emphasising the role of preoperative CT staging.This retrospective study aims to compare preoperative CT-based T-staging with postoperative histopathological T-staging in patients undergoing upfront surgery for biopsy-proven colon adenocarcinoma.Secondary objective includes correlating locoregional lymphadenopathy.

Comprehensive Imaging of Advanced Ovarian Carcinoma: Clinicoradiological Correlation and Prognostic Value of Peritoneal Carcinomatosis Index-Perspectives from an Oncology Institute
Akshat Shah, Priya Ghosh, Saugata Sen Department of Radiology and Imaging, Tata Medical Center-Cancer Hospital and Research Center, Kolkata, West Bengal, India Cancer Imaging (2024),24 (1): P29